Elastic-fluid turbine



Feb 24, 1925.- 1,527,910

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' c. A. PARsoNs ET AL ELASTIC FLUID TURBINE Filed July 5. 1923 6 Sheets-Sheet 5 IINVENTORS: O/AQLES A. AR$oNS ALFKED GAY/V5615 W371 A ffaggfl F1111. 24. 1925. 1,527,910 C. A. PARSONS ET AL ELASTIC FLUID TURBINE Filed July 5, 1923 6 Sheets-Sheet 4 V NTaRS AELEs A Aesmvg Q- CZIQNEGIE.

Feb. 4, 1925. 1,527,910

c. A. PARSONS ET AL ELASTIC FLUID TURBINE Filed July 5, 1923 6 Sheets-Sheet 5 I YENToZS: l/Aklss 4. 83250145 M50 Q. CAN56IF 72] f, W QMQMFJJA Feb. 1925. 1,527,910

c. A. PARSONS ET AL ELASTIC FLUID TURBINE Filed July 5, 1923 6 Sheets$heet 6 MVENTOKS HARLES A. PAKSONS' LFKED CAQNE'/E 7) Sim BHWVW- Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

CHARLES ALGERNON PARSONS AND ALFRED QUINTIN CARNEGIE, F NEWCASTLE- UPON-TYNE ENGLAND; SAID CARNEGIE ASSIGNOR TO SAID PARSONS.

ELASTIC-FLUID TURBINE.

Application filed July 5,

To all whom it may concern! Be itknown that we, CHARLES ALGERNON Pausoxs and Airman QUINTIN CARNEGIE, both subjects of the King of Great Britain and Ireland, and both residing at Heaton Vorks, Newcastle-upon-Tyne, in the county of Northumberland, England, have invented certain new and useful Improvements in and Relating to Elastic-Fluid Turbines, of which the following is. ,;a.'speciflcation.

This invention relates to elastic fluid turbines in which the working fluid is passed successively through rows of blades attached to the stator and rot-or respectively.

In elastic fluid turbines of the class indirated it is necessary to make special provision to prevent anundue proportion of the working fluid from leaking through the clearance spaces between the corresponding parts of the stator and rotor instead of passing through the blades.

A familiar method of sealing these clearance spaces consists in. attaching to the tips of the blades of the rotor and the stator a shroud with a projecting edge which is tapered down to a thin knife-edge so that it may run with safety sensibly in contact with an opposing face on the stator or rotor.

In such cases .it is customary to locate the rotor relatively to the stator definitely at a convenient point in such a way that the knife-edge. shrouds are kept in their proper relation to the opposing faces. It is desirable, however, to provide for a small adjustment of the positions of the fixed and moving blades relative to one another from time to time in order, for instance, to compensate for the differential expansion of the stator and rotor of the turbine with temperature. A fuither reason why it may be desirable to provide for the adjustment of the relative positions of rotor and stator occurs in those elastic fluid turbines which are subjected to thrusttending to movet'he rotor relatively to the stator in an axial direction. The stresses resulting from this thrust may cause a spring or compression in the material of the stator or rotor of such a nature that a 1923. Serial No. 649,549.

made vby hand, as required, and have therefore been dependent on the personal care of an engine-room attendant.

The main object of the present invention 05 is to eliminate the necessity for such hand adjustment.

lVith the objects indicated z The invention consists broadly in an elastic fluid turbine having relatively rotatable blade-carrying elements and automaticallyoperating means for varying bodily their relative longitudinal position.

It will be seen that the relative axial displacement to which rotor and stator are subject under certain working conditions,

e. g., differential expansion due to change of temperature, are in general of a nature in which the relative displacement varies from point to point along the length of the turso bine, while the additional relative displacement compensatory to the above and due to the automatic means provided, is of a bodily nature in which the relative displacement is substantially equal for all points along the length of the turbine.

In addition, owing to the mass of the rotor and the stator, considerable time elapses before these parts attain their working temperature. It is therefore desirable that a. definite interval of time shall elapse before the compensating gear responds fully to the change in the temperature of the operating steam or other fluid.

In particular it is desirable to increase the blade clearaiice spaces by a relatively large Cal amount when the turbine is shut down-and cools and to maintain these increased clearances until a reasonable time after the turbine is re-started and until both stator and rotor have attained a normal running temperature.

With these objects, a further part of the invention consists in means whereby such a delay or time lag is automatically obtained.

According to present practice it is customary to provide locating means to lock the rotor of the turbine in any required longitudinal position in relation to the stator, such locating means comprising a collar on the rotor which runs between two opposing sets of thrust pads carried in the housing in the stator and secured against rotation by any suitable means. The axial distance between the faces of these two sets of thrust pads only exceeds the width of the rotor collar by a very small amount just sufiicient to provide for lubrication. The axial position of the rotor is by this means determined and can be varied at will if gear is provided through which the position of the thrust-block housing can be altered.

It will be clear that this arrangement is practicable in cases where there is a definite thrust on the rotor in the axial direction, as well as in cases where there is no such thrust. In the former case a reaction between the thrust pads at one side or the other balances the end thrust and the housing constitutes a thrust bearing, a term which may be conveniently applied to it whether it is provided to balance an axial thrust or not.

In order to provide for the axial adjustment of the rotor. it is customary to attach to the thrust bearing a mechanism such that by operating a hand wheel or quadrant lever outside the stator, the thrust bearing can be shifted in either direction by a definite amount.

Referring to the accompanying drawings which illustrate different forms of the invention by way of example and form part of the specification Figure 1 shows a sectional plan through as much of a turbine as is necessary to explain the invention, the main controlling rods taking the form of hollow metal bodies heated by steam,

Figure 2 being an enlarged view of the dummy packing;

Figure 3 shows a sectional elevation of a modified form in which the expansion or contraction of the electrically heated controlling rods is transmitted to the thrustbloclc housing by way of a pivoted lever;

Figure 4 shows in elevation another modification, which mutatis mutandis, may be read in conjunction with the plan of Figure 1, in which the main controlling rods are heated indirectly from an adjacent steamboated member,

Figures 5, 6, 7 8, being perspective views to a larger scale of different arrangements suitable for such indirect heating;

Figure 9 shows a sectional plan of a form of the invention in which the time lag can be varied at will.

Finally,

Figure 10 shows an elevation of another form of the invention in which the expansion of the machine itself is utilized instead of that of special control rods, and

Figure 11 a like View of a generally similar arrangement employing a servo-motor;

Figure 12 being a sectional elevation of the controlling valve and easing of the servo-motor to an enlarged scale, and

Figure 13 a ('I'OSSFQClZiOIl on the 11110 13-]3 of Figure 12.

To avoid repetition in the following description, the same reference symbols are where desirable employed in the difl'erent drawings to denote corresponding parts.

In carrying the invention into efiect according to one form (see Figure 1), the shroud, (1, around the blading, b, is in sensible contact with the opposing faces, 0, at the base of the adjoining row of blades, the retor, (1, being provided with a collar, 0, which runs between the two pads or thrust faces, f, 7", which are held in the movable thrustblock housing, 71.

In the enlarged view of the dummy packing shown in Figure 2, the axially disposed fine edges, 2', i, are likewise in sensible contact with the collars, 7:, is, on the rotor body. The clearance spaces between the shroud and its opposing face and between the elements of the dummy packing are therefore determined for any load by the position of the housing, 72, relative to the turbine cylinder, m.

Two hollow rods, 72, 11, having the form of heavy metal chambers are provided and heated internally by steam tapped off from a suitable stage ot the turbine, as shown, and led to these chambers by way of the pipe, 0, and branches, 0', 0. Flow of steam is con trollable by the needle valve, '21, or other finely adjustable valve, by the setting of which the rate of rise of temperature of the main controlling rods, n, a, may be adjusted to allow for the time taken by the mass of the rotor and stator to attain their working temperature. In the form of the invention shown, the metal chambers, 11, '11, serving as controlling rods are drained by way of the pipes, a, connecting the branch pipes, s, s, from the controlling rods to a steam trap, I, so as to prevent undue leakage and allow the steam pressure to rise at the predetermined rate, the chambers, n, being drained by the hand-operated valve, 11, before starting.

The hollow controlling rods, 72, a, are thus maintained continuously at the temperature of the turbine stage from which their heating steam is drawn. In some cases, however, it may be found convenlent to allow a partial cooling in the pipe, 0, so that the steam looses any superheat and keeps the controlling rods at the temperature corresponding to saturation at the pressure of the appropriate stage.

One end of each of the main controlling rods. n, n, is secured as at o, 'v, to the turbine cylinder, the other end of each rod being attached to a connecting bar, w, in WlllCll the outer ends of the pull rods, 2:, m, are located, the inner ends of. the latter being detachably fastened to the thrust-block housing, It.

The pull rods may be rotated by any convenient means such, for example, as the worms, 2, 2, worm spindle, 2, hand wheel, 3, and worm wheels, 4, 4, (see also Figure 4), to provide for initial adjustment of the thrust bearing.

The relation of the parts in Figure 1 is such that a rise in temperature of the working fluid or an increase in load, by causing the controlling rods, 01, into expand, draws the thrust-block housing, 71, towards the left and thus is suitable for the. usual case in which the materials of the rotor and stator are such that the expansion of that part of the rotor between the thrust collar, 0, and

the blading exceeds the expansion of the corresponding portion of the cylinder and so tends to increase the blade clearances.-

In order to obtain the best results it is desirable to grind up the blade shrouds with the machine hot, so that they will be uniformly in contact throughout the whole length of the blading when all parts are at the steady temperatures attained when the plantis operating at its most economical load.

Thefunction of the adjusting gear is then to move the rotor as the load is reduced in the proper direction for increasing the clearances and by such an amount that the shrouds on the row of blades furthest from the. thrust-block have a clearance at least as great as the differential contraction between stator and rotor, so that when the machine cools, the shrouds will not foul the opposing faces. lVhen the machine is cold, the clearance of those blades nearest the thrust-block will be actually greater than the clearances of the blades further away. 3

According to the modification shown in Figure 3, the controlling rods are electrically heated through the medium of coils, 5, instead of by steam. In the particular form shown. the main controlling rod, 12, is arranged in a housing, 6, on the body of the machine, one end being attached to the housing while the other end is attached to a secondary rod, 7, coupled to a lever, 8, pivoted at 9 on the machine, a suitable means of adjustment, such as, for example a differential screw device, bein inter ose between the secondary rod and the ever. The lower end of the lever, 8, is attached by way of the link, 10, and connecting bar, '10, to the pull rods, w, m, and so to the thrustblock housing, h. The secondary rod', 7, which transmits motion to the lever, 8, will attain approximately the same temperature as the main controlling rod, n, and it will therefore be necessary to make the secondary and controlling rods of materials having different coefiicients of expansion.

- The coils, 5, are preferably connected to the alternator in such a manner that the current therein is proportional to the current in one of the phases of the alternator so that the heating effect is proportional to the load. A variable resistance should be provided in circuit with the heating device in order that regulation and adjustment thereof may be made by hand.

The need for a delay in the operation of the adjusting gear due to the mass of the working parts of the machine and the time taken for thenr to attain a constant temperature has already been explained. This object of the invention may also be attained by means of special forms of controlling 'rods one of which is shown in Figure 4.

According to this form the controlling rod consists of two parallel members, 10 and 11, each provided with thin webs, 12, 12, connected by a number of clamping pieces, 13. Steam is passing through the lower of these members, 10, from the turbine, as already described with reference to Figure 1. and the heat travels across the webs, 12, and clamping pieces, 13, to the second member, 11, which functions as the main controlling rod. The structure in question is shown to a larger scale in Figure 5, when in addition, the upper member, 11, is shown with gills or fins, 14.

The time lag may be increased or decreased by an alteration in the length or number of the clamping pieces, 13. Again the webs may be fastened together, as shown in Figure 6, by bolts, 15, and by varying the tension in the bolts or the number of bolts in tension, the rate at which heat is transmitted through the webs from the heated member to the controlling member may be regulated.

Other modifications are shown in Figures 7 and 8. I

In Figure 7, a single web, 16, provided with holes, 17 connects the upper and lower members while in Figure 8 a number of transverse webs, 18, are provided.

In these latter arrangements the controlling rod as in Figure 5 may be provided with gills or for the purpose of increasing the cooling surfaces and accelerating the radiation of heat from the rod.

is utilized instead of the expansion of a main controlling rod. This device is applicable to turbines in which the exhaust end is rigidly fixed to the foundations so that the end in which the thrust-block is housed is free to move axially with variations of temperature and load.

According to one form of this part of the invention, see Figure 10), the axial movement is utilized to, adjust the thrust by attaching a rod, 22, hereinafter referred to as the operating rod, to some convenient point, as for example, the bed plate, 23, to which the turbine is rigidly bolted at the exhaust end, and attaching the other end of the operating rod to a lever, 24, which is pivoted at 25 on the free end of the turbine.

When steam is admitted to the turbine, causing it to expand, the free end will move and carry with it the pivot, 25, of the lever, 24. As the lower end of the lever is connected to the operating rod, 22, the lever will partially rotate on its axis and move the thrust-block by-means of a connecting bar, to, and rods, m, w, as above. This movement of the thrust-block will be proportioned to the movement of the cylinder, the actual ratio of the movements being fixed by the pivot of the lever. Any initial adjustment may conveniently be obtained by means of rightand left-handed threads on the operating rod which may be rotated by a hand wheel, 26, to increase or reduce its eifective length.

A further form of the invention in which the movement of the thrust-block is controlled by the differential expansion of rotor and stator'is shown in Figures 11, 12 and 13. According to this form the pull rods, m, m, are connected to a piston, 27, working within a controlling cylinder, 28, mounted on the frame of the turbine, the position of the piston in the cylinder being defined by oil pressure operating through a relay. The plunger, 29, of the relay is connected byway of a rod, 30, to one end of a lever, 31, pivoted at 32 to the machine, the other end of this lever being in turn connected by the rod, 33, to one end of the lever, 34; this latter lever is pivoted at 35, on a bracket, 36, likewise secured to the machine, its other end being in turn pivoted at 37 to a lug formed on a collar, 38, on the rotor shaft.

A spring, 39, is inserted between 9.0011 on the rod, 30, and the exterior of the casing, 40, in which the plunger works, the casing,

40, being likewise mounted onthe frame of When steam is admitted to, the turbine,

the turbine cylinder heats up more rapidly than the rotor, thereby separating the pivots, 32, 35, of the levers, 31, 34, the length of the rod, 33, remaining substantially constant so that the plunger, 29, is moved relativel to the left in Figure 11 and oil is admitted through the port, 43, to the left of the piston, 27, which thereby moves the rotor to the right in relation to the stator. This motion, however, by Way of the lever, 34, pivoted to the collar, 38, rod, 33, lever, 31 and rod, 30, moves the plunger, 29, to the right, thereby replacing it in its central position. The rotor is thus automatically maintained in a position relative to the stator such that the clearances of the blade shroudings are substantially constant.

It will be understood that the proposals herein described may be applied to achieve the objects in view in a variety of ways and that the examples given merely illustrate some possible methods of application.

Having now described our invention, what we claim as new and desire to secure by Let ters Patent is 1. In combination, relatively rotatable machine eleme ntssubject to relative axial displacement due to certain working conditions and automatic means responsive to changes of temperature for causing a compensatory relative axial displacement, as set forth.

2. In combination, relatively rotatable machine elements subject to differential change of axial dimensions due to certain working conditions and automatic means for causing a compensatory relative axial displacement, as set forth.

3. In combination, ielatively rotatable coaxial machine elements, a thrust bearing in defined relation to one of said elements and means actin automatically in. response to changes of temperature for varying the relative axial position of said bearing and the other of said elements, as set forth.

4. In an elastic fluid turbine, the combination of relatively rotatable co-axial sets of rotor and stator blades subject to relative axial displacement due to certain working conditions and automatic. means for causing a compensatory relative axial displacement, as set forth.

' 5. In an elastic fluid turbine, the combination of relatively rotatable co-axial sets of rotor and stator blades subject to relative axial displacement due to certain working conditions and automatic 111821113 responsive to changes of temperature for causing a compensatory relative axial displacement, as set forth. I

6. In an elastic fluid turbine, the combination of relatively rotatable co-axial sets of rotor and stator blades subject to differential change of axial dimensions due to certain working conditions and automatic means for causing a compensator relative axial displacement, as set forth.

7. In an elastic fluid turbine, the combination of relatively rotatable co-axial sets of rotor and stator blades subject to relative axial displacement of a certain nature under working conditions and automatic means for causing a relative axial displacement of a different nature, as set forth.

8. In an elastic fluid turbine, the combination of relatively rotatable co-axial bladecarrying elements subject to relative axial displacement varying in amount along the length of said blade-carrying elements together with automatically-operated means for superimposing on said displacement an additional relative axial displacement uniform in amount along the length of said blade-carrying elements, as set forth.

9. In an elastic fluid turbine, the combination of blade-carrying rotor and stator, a thrust bearing in defined relation to said rotor and means acting automatically in response to changes of temperature for varying the relative axial position of said thrust bearing and stator, as set forth.

10. In combination, relatively rotatable machine elements subject to relative axial displacement due to certain working conditions, automatic means for causing a compensatory relative axial displacement and means for adjusting the action of said automatic means, as set forth.

11. In an elastic fluid turbine, the combination of a rotor, a stator, and automatically-operating means connecting said rotor and stator for varying bodily their relative longitudinal position, said means including mechanical connecting members, as set forth.

12. In an elastic fluid turbine, the co-m bination of relatively rotatable blade-carrying elements and automatically-operated means connecting said elements for varying bodily their relative longitudinal position, said means including mechanical connecting members, as set forth.

13. In an elastic fluid turbine the combination of relatively rotatable'lblade-carrying elements and means for locating said elements axially 1n relation teens-another,-

change of dimensions of certain of said loeating means acting to cause relative bodily movement between said hlzule-t-arrying elements, as set forth.

14. In an elastic fluid turbine, the combination of a rotor member, a thrust bearing co-acting with said rotor member, a stator member, and means for connecting said thrust bearing With said stator memher, said means including mechanical connecting members, changes of temperature of one of said members automatically acting to cause relative movement of said thrust bearing and said stator member, as set forth.

15. In an elastic fluid turbine, the combination of a blade-carrying rotor, a bladecarrying stator coaxial therewith, and means for automatically varying bodily their relative longitudinal position, said means including an expansible element heated by appropriate means, as set forth.

16. In an elastic fluid turbine, the combination of a blade-carrying rotor, a bladecarrying stator coaxial therewith, and means for automatically varying their relativelongitudinal hollow b0 y to receive heating fluid, as set forth.

17. In an elastic fluid turbine, the combination of a blade-carrying rotor, a bladecarrying stator coaxial therewith, and means for automatically varying their relative longitudinal position, said means including hollow rods heated by the fluid supplied to said turbine, as set forth.

18. In an elastic fluid turbine, the combination of a pair of relatively rotatable coaxial blade-carrying elements capable of bodily relative longitudinal movement, 10- cating means for determining the longitudinal position of said elements, and means operated both automatically and manually for controlling the position of said locating means, asset forth.

19. In an elastic fluid turbine, the combination of a blade-carrying rotor, a bladecarrying stator coaxial there-With,; means for automatically varying their relative longitudinal position, and means including an expansible element and means for heating said element controlled by the load on said turbine, as set forth.

20. In an elastic fluid turbine, a rotor member, a stator member co-axial therewith, automatically-operated means for varying bodily their relative longitudinal positions, and means for effecting a' time lag inthe operation of said automatically-operated means, as set forth.

21. In an elastic fluid turbine, thecombination of a rotor'member, astator' i'nems ber co-axial therewith, automatically-op;.

erated meansfor. varying bodily theirf rela tive longitudinal position, means for auto- 'matically effecting-a time lag in the operaosition, said means including a tion of said automatically-operated means, and means for regulating the degree of said time lag, as set forth. 22. In an elastic fluid turbine having a 5 plurality of expansion stages, the combination of a blade-carryin rotor. a blade-carrying stator co-axial t erewith, and means for automatically varying their relative longitudinal positions, said means including an expansible element and means for heating 10 said expansible element by fluid taken from one of said expansion stages, as set forth.

In testimony whereof we have signed our names to this specification.

CHARLES ALGERNON PARSONS. ALFRED QUINTIN CARNEGIE. 

